PROJECT SUMMARY African Americans have one of the worst health profiles in the US. Prior studies have been unable to completely explain these stark health inequalities, even when accounting for socioeconomic status (SES)?a commonly understood protective factor that has been robustly linked to improvements in health. Growing evidence suggests that upwardly mobile African Americans experience poorer physiological health in early adulthood compared to those from similar backgrounds who remain disadvantaged. The biological and social mechanisms underlying these physiological costs, however, are poorly understood, and the extent to which this pattern applies to other groups remains unknown. Eliminating social inequalities in health requires understanding why minority groups do not enjoy the same health benefits of upward mobility as whites. The proposed study addresses this need by testing biological and social mechanisms linking upward mobility to different health profiles in a nationally-representative sample of young adults from the National Longitudinal Study of Adolescent to Adult Health (Add Health). We will first test the biological mechanism of inflammatory response and immune function?outcomes that are linked to poor health outcomes downstream and are shaped by SES and chronic stressors. Large population based studies, however, generally lack markers of inflammation and immune function, especially in non-aged samples, and consequently, researchers have been unable to explicitly examine their relationship with social mobility. We therefore will conduct novel inflammatory and immune function assays using archived dried blood spots to create a publicly available dataset with five inflammatory and immune markers that are usually unavailable in population studies. Second, we will examine the extent to which upward mobility differentially shapes inflammation and immune function among white, black, and Hispanic young adults, and evaluate the role of environmental incongruence in linking mobility to physiological functioning. Studies have generally focused on individual psychosocial or behavioral mechanisms to explain the observed pattern of poor health among upwardly mobile African Americans. These studies leave unexplored the structural contexts in which mobility occurs, such as one's environment of origin and destination. We hypothesize that upwardly mobile individuals will have higher levels of inflammation and lower immune control compared to their immobile peers, with costs concentrated among minorities. We also expect that dissimilar environmental contexts will be associated with higher levels of inflammation and lower levels of immune control among the upwardly mobile compared to their immobile and environmentally congruent counterparts, particularly among minorities. The information resulting from this study will advance our understanding of complex and intergenerational patterns of health inequality, and create the opportunity for researchers to conduct innovative, multilevel studies of health and well-being.